Protocol Online logo
Top : New Forum Archives (2009-): : Tissue and Cell Culture

Contamination in SH-SY5Y cultures, mycoplasma? - (Jun/02/2010 )

Anyone with experience of mycoplasma- (or other bacteria-) infection of SH-SY5Y cells? How did the cells look and react to that?

I have a contamination in my cultures which shows as a lot of black dots in the cells cytoplasm. In some dishes, also the media contains moving black dots. It also seems as the cells are growing at a slower rate than usual. Could this be mycoplasma? If so, I would not be able to see the bacteria as black dots in the microscope would I? I have tried to grow the bacteria on blood-agar plates but no colonies showed after 4 days. Gram-staining of pellet from the contaminated media did no show any distinct bacteria. I have also tried to throw away everything (cells, media, serum etc) and start with freshly thawed cells and new solutions but the black dots came back after a few days. What could this possibly be?



Cell debris? It is unlikely to be mycoplasma if you can see it. The black dots in the cytoplasm may be mitochondria or other sub-cellular structure, especially if the cells are nearing confluence/ have been cultured a lot.


It is probably not cell debris, because the black dots even show in dishes with only culture media (without any cells) after 3-4 days in the incubator. Also, the dots in the cytoplasm seems to be moving around..